1. Field of the Invention
The present invention relates to a high definition television (HDTV) and more particularly to a method for reducing a carrier recovery time in a HDTV receiver. This application for a method for reducing carrier recovery time in HDTV is based on Korean Patent Application No. 47193/1996 which is incorporated by reference herein for all purposes.
2. Description of the Related Art
In VSB (Vestigial Side Band), DSB (Double Side Band), and SSB (Single Side Band) communication systems, a transmitter transmits a carrier via a pilot signal, in order for a receiver to accurately recover the carrier.
An HDTV receiver detects and demodulates the pilot signal, in order to recover the carrier. However, if there is a big difference between a pilot frequency of the received pilot signal and a local oscillation frequency of a demodulator, it takes a very long time to fully recover the carrier. The higher an offset frequency of the carrier (i.e., the difference between the pilot frequency and the local oscillator frequency) becomes, the lower an output of a frequency error detector becomes. Accordingly, in order to reduce a frequency error, it takes a long carrier recovery time. Therefore, in order to reduce the carrier recovery time, it is needed to detect an extent of the frequency offset and to recover the carrier based upon the detection of the extent of the frequency offset.